Michu struck twice late on to secure the points for the visitors.
Wenger told arsenal.com: "We were not creative, nor sharp. Swansea were more creative and more sharp. They had a lot of possession, but without going anywhere. We tried to change things and took a lot of risks. In the end it turned against us. Maybe we should have made a 0-0 and in the end we were not cautious enough to play the 0-0. The quality of our game was not there. It was a bit frustrating because we lacked a bit of decisiveness and creativity."